Phase scan antenna system



10, 6 R. CONGER ETAL 1 PHASE SCAN ANTENNA SYSTEM Filed NOV. 17. 1959 DIELECTRIC ROD ANTENNA ELEMENTS NON-SCAN SIGNAL COAXIAL PHASE 5 H IFTER SCAN INVENTORS.

ROBERT L. CONGER SIGNAL ROBERT F. RIGGS DALE B. KERN CHARLES E.WH|TE 3,200,401 PHASE SCAN ANTENNA SYSTEM Robert L. Conger, Riverside, Calif., Robert F. Riggs, Charlottesville, Va., and Dale B. Kern, Corona, and Charles E. White, San Bernardino, Califi, assignors to the United States of America as represented by the Secretary of the Navy Filed Nov. 17, 1959, Ser. No. 853,661 3 Claims. (Cl. 343-100) (Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of Arnerica for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to antenna systems and particularly to an antenna system for use in apparatus requiring operation over a large dynamic range. v

The present invention uses an array of dielectric rod antenna elements, with both scan and non-scan signals being obtained from the same antenna by use of an output divider in conjunction with each antenna element.

Previously, separate antennas were required for both scan and non-scan signals, and the antennas needed to be depolarized over as broad a frequency band as possible and matched in polarization over a broad frequency band. The present invention overcomes these disadvantages of prior antenna systems by providing two types of signals from the same antenna and provides an antenna system which is depolarized over a broader bandwidth than conical scan antennas.

It is an object of the invention therefore to provide a novel antenna system in which both scan and non-scan signals are obtained simultaneously from the same antenna.

It is another object of the invention to provide an antenna having depolarization over a broader bandwidth than conical scan antenna.

Still another object of the invention is to provide an antenna system for operational use over a large dynamic range.

A further object of the invention is to provide .an antenna system wherein an output divider is used in conjunction with each of a plurality of antenna elements for simultaneously obtaining more than one type of signal from each antenna element.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

The figure is a schematic diagram of one embodiment of the present invention showing a three-rod antenna systern.

Referring now to the drawing, the embodiment disclosed herein, by way of example, uses an array of three antenna elements. As shown in the figure, the invention uses a group of three dielectric rod antenna elements 10 with helical feeds 12. Such antenna elements are disclosed in copending US. patent application Serial No. 853,659 for Helical Feed Dielectric Rod Antenna, filed November 17, 1959 and now abandoned. The output of each of the antenna elements 10 goes to an isolating device 14, such as a coaxial magic T, for example, .and is divided into two parts. One-half of the signal from each antenna element It goes to junction 16, and the output of junction 16 is the non-scanning signal of the antenna system. The function of an isolating device 14 is to keep all the antenna elements 10 from being interconnected through junction 16. The other half of the signal from each antenna element 19 goes to a phase shifter 18, such as a coaxial phase shifter of the type disclosed in United States Patent copending US, patent application Serial No. 853,662, for Radio-Frequency Coaxial Transmission Phase Shifter, filed Nov. 17, 1959, now US. Patent No. 3,017,587, issued Jan. 16, 1962. The output of phase shifter 18, at junction 20, provides the scan signal from the antenna system. There is no difference between the scan signal and the non-scan signal; as indicated above, the output from each antenna It) is merely split into two parts one which is fed to junction 16 and the other which goes to phase shifter 18. The non-scan portion of the output from the antennas is called non-scan merely because it is the portion of the signal that is not used for scanning purposes. Splitting the signal into scan and nonscan portions, by means of isolating devices 14 has two particular advantages: first, if an AGC signal or the like were taken from point 29, (Le. from the scan signal) a portion of the scanning information would be removed, and, secondly, by taking AGC signals and the like from point 16 (i.e. from the non-scan signal which lay-passes phase shifter 18) there can be no feedback, because of isolating device 14, that can interfere with scanning information.

In the present invention the isolating devices 14 permit both a scan signal and a non-scan signal to be obtained simultaneously from the same antenna, and the use of an array of dielectric rod antenna elements equi distantly spaced from each other having helical feeds to form a depolarized antenna provides an antenna system having greater bandwith than heretofore. The present invention mayalso be constructed in smaller sizes than similar antennas, known heretofore.

The direction in which the present antenna system is pointed can be changed by introducing additional phase shift 13, by any desired conventional means, into the lines from antenna elements 10. For example, additional phase delay in the line from the lowest positioned antenna element It of a present antenna system array will cause the antenna system to look downward; whereas, in prior art systems it was necessary to tip the entire system downward mechanically to accomplish this, The saving in power required to point the present antenna system downward electronically by introducing additional phase shift is one of its advantages over prior systems. In addition, the electronically controlled phase shift for pointing the present antenna system can be operated easily by a control gyroscope.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A multi-probe phase scan antenna system for operation over a large dynamic range comprising three dielectric rod antenna elements spaced equidistantly from each other to form an array thereof, three coaxial magic-T isolating devices, and a coaxial phase shifter, the signal output of each of said antenna elements being connected through respective transmission lines to a respective one of said isolating devices, each of said isolating devices being operable to divide the signal output from 7 its respective antenna element into two parts, one part devices also operating to prevent all of said antenna elements from being interconnected and preventing any feedback from said first junction to said second junction, the direction in which the antenna system is looking being changed if desired without mechanically pointing the antenna system by introducing additional phase shift into any of the lines from said antenna elements, whereby said antenna system is depolarized and both scan and non-scan signals are obtained from the antenna array of elements.

2. A phase scan antenna system for operation over a large dynamic range comprising three dielectric rod antenna elements spaced equidistantly from each other to form an array thereof, three magic-T isolating means, and a coaxial phase shifter, the signal output of each of said antenna elements being connected through respective transmission lines to a respective one of said isolating means, each of said isolating means being operable to divide the signal output from its respective antenna element into two parts, one part of said divided signal output from each of said isolating means being fed through transmission lines to a first junction, the output of said first junction being the non-scanning signal from said antenna system, the other part of said divided signal output from each of said isolating means being fed through transmission lines to respective inputs of said coaxial 5 vent all of said antenna elements from being interconnected and preventing any possible feedback from said first junction from reaching said second junction, whereby said antenna system is depolarized and both scan and non-scan signals are obtained from the antenna array 10 of elements.

3. An antenna system as in claim 2 wherein said dielectric rod antenna elements each have helical feeds.

References Cited by the Examiner UNITED STATES PATENTS 2,041,600 5/36 Friis 343-400 2,245,660 6/38 Feldrnan et al. 343-400 2,444,425 7/58 Busignies s- 343-100 20 2,848,714 8/58 Ring 343l00 2,878,472 3/59 Sterns 343l00 CHESTER L. JUSTUS, Primary Examiner.

KATHLEEN H. CLAFFY, FREDERICK M. STRA- DER, Examiners. 

1. A MULTI-PROBE PHASE SCAN ANTENNA SYSTEM FOR OPERATION OVER A LARGE DYNAMIC RANGE COMPRISING THREE DIELECTRIC ROD ANTENNA ELEMENTS SPACED EQUIDISTANTLY FROM EACH OTHER TO FORM AN ARRAY THEREOF, THREE COAXIAL MAGIC-T ISOLATING DEVICES, AND A COAXIAL PHASE SHIFTER, THE SIGNAL OUTPUT OF EACH OF SAID ANTENNA ELEMENTS BEING CONNECTED THROUGH RESPECTIVE TRANSMISSION LINES TO A RESPECTIVE ONE OF SAID ISOLATING DEVICES, EACH OF SAID ISOLATING DEVICES BEING OPERABLE TO DIVIDE THE SIGNAL OUTPUT FROM ITS RESPECTIVE ANTENNA ELEMENT INTO-TWO PARTS, ONE PART OF SAID DIVIDED SIGNAL OUTPUT FROM EACH OF SAID ISOLATING DEVICES BEING FED THROUGH TRANSISSION LINES TO A FIRST JUNCTION, THE OUTPUT OF SAID FIRST JUNCTION BEING THE NON-SCANNING SIGNAL FROM SAID ANTENNA SYSTEM, THE PART OF SAID DIVIDED SIGNAL OUTPUT FROM EACH OF SAID ISOLTAING DEVICES BEING FED THROUGH TRANSMISSION LINES TO RESPECTIVE INPUTS OF SAID COAXIAL PHASE SHIFTER, RESPECTIVE OUTPUTS OF SAID COAXIAL PHASE SHIFTER BEING FED TO SECOND JUNCTION, THE OUTPUT OF SAID SECOND JUNCTION BEING THE SCANNING SIGNAL FROM SAID ANTENNA SYSTEM, SAID ISOLATING DEVICES ALSO OPERATING TO PREVENT ALL OF SAID ANTENNA ELEMENTS FROM BEING INTERCONNECTED AND PREVENTING ANY FEEDBACK FROM SAID FIRST JUNCTION TO SAID SECOND JUNCTION, THE DIRECTION IN WHICH THE ANTENNA SYSTEM IS LOOKING BEING CHANGED IF DESIRED WITHOUT MECHANICALLY POINTING THE ANTENNA SYSTEM BY INTRODUCING ADDITIONAL PHASE SHIFT INTO ABY OF THE LINES FROM SAID ANTENNA ELEMENTS, WHEREBY SAID ANTENNA SYSTEM IS DEPOLARIZED AND BOTH SCAN AND NON-SCAN SIGNALS ARE OBTAINED FROM THE ANTENNA ARRAY OF ELEMENTS. 